The acorn, or oaknut, is the nut of the oaks and their close relatives (genera Quercus and Lithocarpus, in the family Fagaceae).It usually contains one seed (occasionally two seeds), enclosed in a tough, leathery shell, and borne in a cup-shaped cupule.Acorns are 1–6 cm (1 ⁄ 2 – 2 + 1 ⁄ 2 in) long and 0.8–4 cm (3 ⁄ 8 – 1 + 5 ⁄ 8 in) on the fat side.

RISC OS / r ɪ s k. oʊ ˈ ɛ s / is a computer operating system originally designed by Acorn Computers Ltd in Cambridge, England.First released in 1987, it was designed to run on the ARM chipset, which Acorn had designed concurrently for use in its new line of Archimedes personal computers. RISC OS takes its name from the reduced instruction set computer (RISC) …